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147 lines
5.0 KiB
ArmAsm
147 lines
5.0 KiB
ArmAsm
;/*
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; FreeRTOS.org V5.4.0 - Copyright (C) 2003-2009 Richard Barry.
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;
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; This file is part of the FreeRTOS.org distribution.
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;
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; FreeRTOS.org is free software; you can redistribute it and/or modify it
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; under the terms of the GNU General Public License (version 2) as published
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; by the Free Software Foundation and modified by the FreeRTOS exception.
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; **NOTE** The exception to the GPL is included to allow you to distribute a
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; combined work that includes FreeRTOS.org without being obliged to provide
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; the source code for any proprietary components. Alternative commercial
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; license and support terms are also available upon request. See the
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; licensing section of http://www.FreeRTOS.org for full details.
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;
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; FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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; more details.
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;
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; You should have received a copy of the GNU General Public License along
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; with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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; Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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;
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;
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; ***************************************************************************
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; * *
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; * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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; * *
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; * This is a concise, step by step, 'hands on' guide that describes both *
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; * general multitasking concepts and FreeRTOS specifics. It presents and *
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; * explains numerous examples that are written using the FreeRTOS API. *
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; * Full source code for all the examples is provided in an accompanying *
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; * .zip file. *
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; * *
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; ***************************************************************************
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;
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; 1 tab == 4 spaces!
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;
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; Please ensure to read the configuration and relevant port sections of the
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; online documentation.
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;
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; http://www.FreeRTOS.org - Documentation, latest information, license and
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; contact details.
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;
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; http://www.SafeRTOS.com - A version that is certified for use in safety
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; critical systems.
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;
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; http://www.OpenRTOS.com - Commercial support, development, porting,
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; licensing and training services.
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;*/
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INCLUDE portmacro.inc
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IMPORT vTaskSwitchContext
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IMPORT vTaskIncrementTick
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EXPORT vPortYieldProcessor
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EXPORT vPortStartFirstTask
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EXPORT vPreemptiveTick
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EXPORT vPortYield
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VICVECTADDR EQU 0xFFFFF030
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T0IR EQU 0xE0004000
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T0MATCHBIT EQU 0x00000001
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ARM
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AREA PORT_ASM, CODE, READONLY
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Starting the first task is done by just restoring the context
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; setup by pxPortInitialiseStack
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortStartFirstTask
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PRESERVE8
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portRESTORE_CONTEXT
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vPortYield
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PRESERVE8
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SVC 0
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bx lr
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Interrupt service routine for the SWI interrupt. The vector table is
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; configured in the startup.s file.
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;
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; vPortYieldProcessor() is used to manually force a context switch. The
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; SWI interrupt is generated by a call to taskYIELD() or portYIELD().
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPortYieldProcessor
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PRESERVE8
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; Within an IRQ ISR the link register has an offset from the true return
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; address, but an SWI ISR does not. Add the offset manually so the same
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; ISR return code can be used in both cases.
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ADD LR, LR, #4
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; Perform the context switch.
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portSAVE_CONTEXT ; Save current task context
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LDR R0, =vTaskSwitchContext ; Get the address of the context switch function
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MOV LR, PC ; Store the return address
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BX R0 ; Call the contedxt switch function
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portRESTORE_CONTEXT ; restore the context of the selected task
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Interrupt service routine for preemptive scheduler tick timer
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; Only used if portUSE_PREEMPTION is set to 1 in portmacro.h
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;
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; Uses timer 0 of LPC21XX Family
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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vPreemptiveTick
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PRESERVE8
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portSAVE_CONTEXT ; Save the context of the current task.
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LDR R0, =vTaskIncrementTick ; Increment the tick count.
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MOV LR, PC ; This may make a delayed task ready
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BX R0 ; to run.
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LDR R0, =vTaskSwitchContext ; Find the highest priority task that
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MOV LR, PC ; is ready to run.
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BX R0
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MOV R0, #T0MATCHBIT ; Clear the timer event
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LDR R1, =T0IR
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STR R0, [R1]
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LDR R0, =VICVECTADDR ; Acknowledge the interrupt
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STR R0,[R0]
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portRESTORE_CONTEXT ; Restore the context of the highest
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; priority task that is ready to run.
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END
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